New ILS Commissioning

[Tom the Tenor]

If I may I should like to pose a few questions about the putting in of new ILS systems. I am not technically minded so please forgive me for if my questions are posed in a rough sort of way.

In June the ILS at Cork which is CAT I/II is to be decommissioned for two reasons: (i) The ongoing building work of the new terminal and the new multi-storey car park and (ii) The Irish Aviation Authority wish to use the opportunity to install a new ILS. The present ILS is thirteen years old.

Cork suffers a lot from poor weather due to sea fog and low cloud as Cork is at about 500 feet AMSL. The CAT II availability for approaches has saved Cork from many, many diversions which would have all been lost if Cork had remained at only CAT I.

The IAA say the ILS will be off the air completely from June to August. Now, the rub is that the new CAT II is expected to be down from about six months to a year whilst it is being tested.

Is this normal practice? Would this happen at DUB or LHR?

If so, are there any alternatives to ILS available for low visibility approaches at a field like Cork where the weather can be regularly below CAT I minima?

Thank you. A big hello from Cork! :)

[DFC]

It's at times like that when everyone wishes that they hadn't got rid of the PAR.

The exact reasons for having the system off air may not be as simple as it first seems.

Having replaced the equipment and checked it from the ground, it is a requirement to complete flight testing using calibrator aircraft. I don't know who the IAA have contracted to do the calibraton but it is probably the former CAA unit located at Teesside.

Making a booking will of course be subject to the calibrator having an available slot. It also makes sense to have the Cork calibration done at a time when the aircraft is already in Ireland doing another job.

There is also the weather factor and decent weather is required for the calibration work.

Having installed the system and had it calibrated, there are limits to the movement of ground vehicles and to the positioning of objects on the ground (which could be associated with on-going work) which can have an effect on the radiated signals.

Thus when making a judgement call on such a project, lots of factors must be considered which in the end may not actually cause a delay and if that si the case, the IAA can say they put the system on line ahead of schedule.

As for something to do when the weather is too low and the ILS is not available - noting other than divert is the answer but remembering that if the system was not replaced, there could be plenty of unexpected diversions due to ground equipment failure during the following winters.

Regards,

DFC

[Tom the Tenor]

Thank you, DFC, for your thoughtful reply to my queries. I am going to read and think over your reply for a little while, if I may. Thank you, TtT. :)

[Downwind.Maddl-Land]

I think you'll find that the safety regulator will want evidence of the reliability of the new kit and it will have to radiate for a specified number of hrs, without failure, before it can be brought into service. By the way, the IAA's Calibration service is provided by Flight Precision Ltd (FPL) a very successful private calibration company; see their website www.flightprecision.co.uk. FPL traces is roots back to the Flight Checking Service and 115 Sqn, RAF. ;)